The Association between Urinary N-Acetyl-ß-D-Glucosaminidase and Cardiovascular Autonomic Neuropathy in Patients with Diabetes

Abstract

Background: Cardiovascular autonomic neuropathy (CAN) is a microvascular complication of diabetes, which involves autonomic nerve fibers innervating the heart and vessels, resulting in increased cardiovascular morbidity and mortality. Previous studies reported that diabetic CAN is related to microalbuminuria. However, it is unclear whether CAN is related with urinary N-acetyl-β-D-glucosaminidase (uNAG), which was suggested as an early marker of renal tubular injury in diabetic nephropathy recently. Methods: Cross-sectional data of 1052 patients with diabetes were analyzed who had tests for uNAG and autonomic function test at outpatient clinic. The presence and severity of CAN were assessed by the five autonomic function tests. Results: The association between uNAG and the presence of CAN in patients with type 1 diabetes (T1D) (n=161) was significant in multivariate analysis (OR 1.20, 95% CI 1.03-39; p = 0.018) after correction of variables including age, duration of diabetes, glycemic index and albuminuria, but it was insignificant in patients with type 2 diabetes (T2D) (n=891). Among quartile groups divided by uNAG levels, prevalence of CAN was significantly increased across with higher quartiles of uNAG level only in patients with T1D (p = 0.013). The association between uNAG and the total CAN score, assessed as the severity of CAN, was significant in both patients with T1D (p = 0.033) and T2D (p = 0.006) in multivariate analyses. Conclusion: Elevated uNAG is associated with the prevalence of CAN only in patients with T1D, and it is also related to the severity of CAN in both patients with T1D and T2D. It suggests that elevated uNAG might be a potential marker for the development and progression of CAN in patients with diabetes. Disclosure M. Choi: None. J. Jun: None. G. Kim: None. S. Jin: None. K. Hur: None. M. Lee: None. J. Kim: None.